Dental apparatus



DENTAL APPARATUS Filed July 26, 1952 \54/ 515 awe/m d 55 56 John MCragyo Patented Nov. 7, 1933 UNITED STATES PATENT OFFICE Claims.

This invention relates to dental apparatus which is adapted to be used for compressing amalgam and extracting mercury therefrom in the operation of packing amalgamdies- Here- 5 tofore, it has been theusual procedure for the dentist to about half fill the impression with amalgam and to place the remaining amalgam in a chamois or the like, twisting the ends thereof to retain the amalgam therein. The dentist,

heretofore, has then, with his hands, squeezed the amalgam in the chamcis so as to express the excess mercury from the amalgam, permitting the expressed mercury to fall upon the table or bench at which he is working. This mercury picks up extraneous matter and becomes unsanitary and unfit for future use. This expressing by hand is a rather laborious and relatively long operation and one in which all of "the excess mercury is not always expressed.

It is an object of the present invention to provide an improved apparatusof thischaracter in which means are provided for catching the expressed mercury and preserving the same in a clean and sanitary condition for future use.

Another object of the present invention is to provide an improved apparatus for packing amalgam dies in which all the excess mercury may be quickly and easily expressed from the amalgam in the chamois.

A further object of the present invention is toprovide an improved apparatus of this character which comprises few parts, is relatively simple in construction, is cheap to manufacture, and is very efficient in operation.

Other objects will be in part obvious, and in part pointed out more in detail hereinafter.

The invention accordingly consists in the features of construction, combination of elements and arrangement of parts which will be exem- 40 plified in the construction hereinafter set forth and the scope of the application of which will be indicated in the appended claims.

In the accompanying drawing, wherein is shown, for illustrative purposes, one embodiment which the present invention may take,

Fig. 1 is a view partly in elevation and partly in section of my improved apparatus showing the same assembled for expressing the excess mercury from the amalgam;

Fig. 2 is a fragmentary view, partlyv in elevation and partly in section, ,of my improved apparatus assembled for compressing and packing the amalgam into an impression; V Fig. 3 is a fragmentary view, partly in ele- ,55 vation and partly-in section, of my improved apparatus showing the same after it has completed the packing of an impression;

Fig. 4 is a side elevation of my ring holder;

Fig. 5 is a fragmentary View, partly in elevation and partly in section, of my improved apparatus assembled for packing a dowel in an impression; and" 1 Fig. 6 is a perspective view of a guide washer.

Referring more particularly to the drawing, 10' designates the base of my improved apparatus, 11 represents a standard arising from the base, and 12 designates a head carried by'the upper end of the standard and overhanging the base. Mounted for vertical sliding movement inthe head is a rack bar 13 which may be raised or lowered by means of a pinion 14 carried by the head 12 and meshing with the rack bar 13. The pinion 14 may be rotated by means of a handle 15. The lower end of the rack bar is provided with a downwardly opening recess 16. An opening 17 is provided in one side wall of the rack bar 13, and the inner end of this opening communicates with the recess 16 of the-rack bar. The opening 1'] is interiorly screw threaded and is adapted to receive therein a binding screw 18.

The recess 16 of the rack bar 13 is adapted to receive therein the shank 19 of a ring holder 20 which comprisesa substantially cylindrical body portion open at its lower end and closed at its upper end by a bottomfrcm which the shank 19 extends. intermediate its ends with a circumferential groove 23 which is adapted to receive the inner end of the binding screw 18 when the shank is disposed in the recess 16 of the rack bar. The wall of the ring holder 20 is provided with a pair of diametrically opposed bayonet slots 24.

The ring holder 20 is adapted to selectively and removably receive a mercury extractor 25 and an impression ring 26. The mercury extractor 25 comprises a substantially cylindrical plug the wall of which is provided with a pair of diametricallyopposed pins 25' which are adapted to be respectively received by the slots 24 of the ring holder 20 when the extractor is disposed within the ring holder. The lower face of the extractor is provided with a dome-shaped recess 27.

The base 10 of the apparatus is adapted to This shank 19 is provided V supportthereon in vertical alinement with the cylinder 20 a casing A having alower section 28 provided with a bottom 29 from whichextends a shank or stem '30. When the casing A is disposed upon the base 10, the shank 30 thereof is received by an opening 31 in the base and the bottom of the casing will rest upon the upper face of the base. Within the casing and spaced from the inner wall thereof, the bottom 29 of the casing is provided with an upstanding boss 32 having a bore 33 extending downwardly into the shank 30. The space defined by the inner wall of the casing and the outer wall of the boss 32 constitutes a reservoir 34.

Mounted for vertical sliding movement in the bore 33 is a stem 36 carrying at its upper end an amalgam supporting plunger 37, the lower end of which is provided with a valve head 38. The plunger also includes a cap or disc 39 having a stem or shank 40 removably received by a recess 41 in the member 37.

The casing A is open at its upper end and the upper portion of the casing comprises a section 42 the upper wall of which slopes downwardly and inwardly towards said opening. The section 42 may be formed integral with the lower section 28 of the casing A but is shown herein as separate therefrom and is provided with a depending skirt 42 the outer wall of which engages the upper portion of the inner wall of the section 28. The outer wall of the skirt is provided with a circumferential groove 44 which receives the inner ends of binding screws 45 carried by the wall of section 28 of the casing A. It will be noted that the skirt 43 is spaced inwardly from the outer wall of the section 42 so that an annular shoulder is provided thereon which rests upon the upper surface of the wall of the section 28 of the casing A. The inner wall of the skirt 43 is provided with a downwardly and inwardly facing annular valve seat 46 against which the valve head 38 is normally engaged. Disposed within the recess 33 beneath the stem 36 is a coil spring 47, by means of which the valve head 38 is normally urged upwardly so that it is normally engaged with the valve seat 46.

The ring 26 is provided with a pair of diametrically opposed pins 48 which are adapted to be received by the bayonet slots 24 of the holder 20 when the ring is disposed in the holder. The ring 26 is adapted to be filled with a stone or plaster 49 in which is embedded an impression 50.

In the use of my improved apparatus, the dentist or other operator wraps a thin piece of wax (not shown) about one-half inch in width, around the impression 50 and seals the wax with a warm spatula. He then lubricates the ring with Vaseline or the like (not shown) and fills the same with the stone or plaster 49 which is preferably a fifteen minute stone. The impression 50 is then embedded in the plaster and, when the plaster has set, the plaster and the wax are trimmed even with the ring.

The casing A is then seated in the base 10 of the apparatus and assuming that the ring holder 20 is in position in the rack bar 13, the mercury extractor 25 is placed in the ring holder. The amalgam is then mixed in the usual manner and the impression 50 is about half filled with the amalgam and the ring is tapped ten or fifteen times on the base of the machine. The remaining amalgam is placed in a chamois 51 or the like, shown in Fig. 1, and the chamois is twisted to retain the amalgam therein. The chamois with the amalgam therein is placed on the cap 39 and the handle 15 is then operated to move the rack bar 13 downwardly to bring the extractor into a position in which the recess 27 thereof receives the amalgam in the chamois 51 and the extractor will squeeze the amalgam between itself and the cap 39 to express the excess mercury from the amalgam. It will be noted that during this squeezing operation the support 37 is depressed and the valve head 38 is moved out of engagement with the valve seat 46 thereby permitting the expressed mercury 52 to enter the reservoir 34 of the casing A. When all of the excess mercury has been expressed, the handle 15 is operated in the opposite direction to raise the rack bar and the extractor. Thus relieved of the downwardly exerted pressure, the support 37, under the influence of the spring 4'7, will move upwardly until the valve head 38 engages the valve seat 46 and thus the casing A will be closed and the mercury contained in the reservoir 34 will be preserved in a clean and sanitary condition until used.

The dry amalgam is now removed from the chamois and deposited in the half filled impression 50 so that a mound 53 of amalgam extends out of the impression, as shown in Fig. 2. The extractor is then removed and the ring 26 placed in the ring holder 20. The handle 15 is again operated to bring the rack bar down so that the impression 50 and mound 53 of the amalgam are brought into engagement with the cap 39 whereby the amalgam is packed into the impression. During this operation, more mercury is expressed from the amalgam, and the support 37, and valve head 38, are depressed as before so that the reservoir is opened to receive the expressed mercury 54, as shown in Fig. 3.

The ring 26 is removed from the ring holder and the excess amalgam cut away. The position of the ring is then reversed in the ring holder and the handle of the apparatus is struck a slight blow by the hand of the operator to bring the stone into sharp contact with the cap 39 to remove the stone and impression from the ring. It will be understood that the pins 48 on the ring 26 are so disposed that when the ring 26 is inverted in the holder 20 there will be a space provided between the inner end of the stone and the bottom of the holder 20 to allow the stone to bounce out of the ring. After the amalgam has set, the stone and impression may be separated by placing the stone upon an anvil and then striking it lightly with a hammer. The amalgam die may then be removed from the impression in the usual way, the die trimmed by means of an abrasive wheel.

To pack a dowel in the impression, the prog extending from the impression and surrounding the dowel. The cap 39 is removed and a washer 57 which may be an ordinary metal washer hav- Ill) ill!) .xuu

ing an over all diameter substantially the same j as that of the open end of the support 37 and having a centrally disposed opening 58 of substantially the same diameter as that or the dowel is disposed upon the upper end of the support 37 with the opening in the washer in registry with the opening in the support 37. When the rack bar and impression are moved downwardly, the mound 56 of amalgam will be packed by the blank portion of the washer into the impression around the embedded end of the i-lo dowel and the free end of the dowel will be received by the hole in the washer and the recess 41 in the support 37. The support 37 and its valve head 38 will be depressed as before to permit the expressed mercury to flow into the reservoir 34.

As many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the language used in the following claims is intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

I claim as my invention:

1. In a dental apparatus for use in compressing amalgam and extracting mercury therefrom, a casing having a reservoir chamber provided with an opening in its upper end, said casing having its upper wall sloping towards said opening and provided with a valve seat surrounding said opening, a plunger extending through said opening and having its upper end extending above said casing and adapted .to support the amalgam, said plunger having a valve head adapted to engage the valve seat, and a spring normally urging said plunger upwardly to engage said valve head against the seat, said plunger, when pressure is brought against the amalgam resting thereon, being adapted to unseat the valve head, whereby the expressed mercury will flow into said reservoir.

2. In a dental apparatus for use in compressing amalgam and extracting mercury therefrom,

a casing having a reservoir chamber provided with an opening in its upper end, said casing having its upper wall sloping towards said opening and provided with a valve seat surrounding said opening, a plunger extending through said opening and having its upper end extending above said casing and adapted to engage the amalgam, said plunger having a valve head adapted to engage said valve set, and means for normally urging said plunger upwardly to engage said valve head against said seat, said plunger, when pressure is brought against the amalgam engaging thereagainst, being adapted to move downwardly to unseat the valve head, whereby the expressed mercury will flow into said reservoir.

3. In a dental apparatus for use in compressing amalgam and extracting mercury therefrom, a casing having a reservoir chamber provided with an opening in its upper end, said casing having its upper wall sloping towards said opening and provided with a valve seat surrounding said opening, a plunger extending through said opening and having its upper end extending above said casing, said plunger also having a cap disposed at its upper end and adapted to engage the amalgam, said plunger having a valve head adapted to engage said valve seat, and means for normally urging said plunger upwardly to engage said valve head against said seat, said plunger, when pressure is brought against the amalgam engaging thereagainst, being adapted to move downwardly to unseat the valve head, whereby the expressed mercury will flow into said reservoir.

4. In a dental apparatus for use in compressing amalgam around a dowel and extracting mercury therefrom, a casing having a reservoir chamber provided with an opening in its upper end, said casing having its upper wall sloping towards said opening and provided with a valve seat surrounding said opening, a plunger extending through said opening and having its upper end extending above said casing, said plunger also having a recess in the upper end thereof and a washer adapted to engage the amalgam and having an opening therein adapted to register with said recess, said plunger having a valve head adapted to engage said valve seat, and means for normally urging said valve seat against said seat, said plunger, when pressure is brought against the amalgam engaging said washer, being moved downwardly to unseat said valve head, whereby the expressed mercury will flow into said reservoir, said alined recess and opening adapted to accommodate the end of the dowel which is not embedded in the amalgam.

5. In a dental apparatus for compressing amalgam and extracting mercury therefrom, a

base having an overhead standard, said base having an opening, a member mounted for vertical reciprocation in the overhanging portion of said standard and in vertical alinement with said opening, a casing supported on said base and having a shank engaging in said opening, 1

the supper wall of said casing having a central opening and said wall sloping downwardly towards said opening, said casing also having a valve seat surrounding said opening, a plunger extending through said opening and having its upper end extending above said casing in opposition to said reciprocating member, said plunger having a valve head adapted to, engage said seat, a spring beneath said plunger for normally urging said valve head to its seat, and an element removably carried by the lower end of said reciprocating member and adapted to cooperate with the upper end of said plunger to extract mercury from the amalgam placed therebetween.

JOHN M. CRAIGO. 

